From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-btrfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com,
hch@lst.de, cluster-devel@redhat.com, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails
Date: Wed, 8 Jul 2020 16:19:22 -0500 [thread overview]
Message-ID: <20200708211926.7706-3-rgoldwyn@suse.de> (raw)
In-Reply-To: <20200708211926.7706-1-rgoldwyn@suse.de>
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
For direct I/O, add the flag IOMAP_DIO_RWF_NO_STALE_PAGECACHE to indicate
that if the page invalidation fails, return back control to the
filesystem so it may fallback to buffered mode.
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
fs/iomap/direct-io.c | 8 +++++++-
include/linux/iomap.h | 14 ++++++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 2753b7022403..66becf935865 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -484,8 +484,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
*/
ret = invalidate_inode_pages2_range(mapping,
pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
- if (ret)
+ if (ret) {
+ if (dio_flags & IOMAP_DIO_RWF_NO_STALE_PAGECACHE) {
+ if (ret == -EBUSY)
+ ret = 0;
+ goto out_free_dio;
+ }
dio_warn_stale_pagecache(iocb->ki_filp);
+ }
ret = 0;
if (iov_iter_rw(iter) == WRITE && !wait_for_completion &&
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 80cd5f524124..a68705369a2c 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -262,7 +262,21 @@ struct iomap_dio_ops {
/*
* Wait for completion of DIO
*/
+
#define IOMAP_DIO_RWF_SYNCIO (1 << 0)
+/*
+ * Direct IO will attempt to keep the page cache coherent by
+ * invalidating the inode's page cache over the range of the DIO.
+ * That can fail if something else is actively using the page cache.
+ * If this happens and the DIO continues, the data in the page
+ * cache will become stale.
+ *
+ * Set this flag if you want the DIO to abort without issuing any IO
+ * or error if it fails to invalidate the page cache successfully.
+ * This allows the IO submitter to fallback to buffered IO to resubmit
+ * IO
+ */
+#define IOMAP_DIO_RWF_NO_STALE_PAGECACHE (1 << 1)
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
--
2.26.2
next prev parent reply other threads:[~2020-07-08 21:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 21:19 [PATCH 0/6 v11] btrfs direct-io using iomap Goldwyn Rodrigues
2020-07-08 21:19 ` [PATCH 1/6] iomap: Convert wait_for_completion to flags Goldwyn Rodrigues
2020-07-08 21:19 ` Goldwyn Rodrigues [this message]
2020-07-08 21:19 ` [PATCH 3/6] btrfs: switch to iomap_dio_rw() for dio Goldwyn Rodrigues
2020-07-08 21:19 ` [PATCH 4/6] fs: remove dio_end_io() Goldwyn Rodrigues
2020-07-08 21:19 ` [PATCH 5/6] btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK Goldwyn Rodrigues
2020-07-08 21:19 ` [PATCH 6/6] btrfs: split btrfs_direct_IO to read and write part Goldwyn Rodrigues
-- strict thread matches above, loose matches on Subject: below --
2020-06-29 19:23 [PATCH 0/6 v10] btrfs direct-io using iomap Goldwyn Rodrigues
2020-06-29 19:23 ` [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails Goldwyn Rodrigues
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